[20] A summary of his argument is given in "The Evolution of Sex," by P. Geddes and J. Arthur Thomson. Walter Scott, London. Revised edition, 1901.
The next step was an inductive verification of these a priori inferences, and here Spencer utilised a wealth of evidence drawn from a wide survey of the animal and vegetable world. He measured individuation by amount of growth, degree of development, and fullness of activity, and his result always was that genesis and individuation vary inversely. To the question: How is the ratio established in each special case? Spencer answered: By Natural Selection. According to the particular conditions of the species, natural selection determines whether the quantity of matter spared from individuation for genesis be divided into many small ova or a few large ones; whether there shall be small broods at short intervals or larger broods at longer intervals; or whether there shall be many unprotected offspring, or a few carefully protected by the parent. In other words, natural selection determines the particular form which the antithesis between individuation and genesis will take. Finally, Spencer introduced the following qualification. If time be left out of account, or if species be considered as permanent, then the inverse ratio between individuation and genesis holds absolutely, but each advance in individual development implies an economy: the advantage must exceed the cost, else it would not be perpetuated. The organism has an augmentation of total wealth to share between its individuation and its genesis, and though the increment of individuation tends to produce a corresponding decrement of genesis, this latter will be somewhat less than accurately proportionate. In short, genesis decreases as individuation increases, yet not quite so fast. If the species be evolving, the advance in individuation implies a certain economy, of which a share may go to diminish the decrement to genesis.
Spencer then extended his hard-won generalisation to the case of man, in which, as everyone knows, very high individuation is associated with all but the lowest rate of multiplication. The same antithesis is seen on comparing different races or nations, or even different social castes or occupations. Where there is relatively low individuation, or where nutrition is in obvious excess of expenditure required to get it, there high multiplication prevails. Reviewing the various possibilities of progressive human evolution, he concluded that this must take place mainly on the psychical side. Hence the corollary that the culture of man's psychical nature constantly tends to diminish the rate of fertility, and pressure of population, which Spencer regarded as the main incentive to progress, tends to disappear as it achieves its full effect. The acute pressure of population, with its attendant evils, thus tends to cease as a more and more highly individuated race busies itself with its increasingly complex yet normal and pleasurable activities, its rate of reproduction meanwhile descending towards that minimum required to make good its inevitable losses.
This was Spencer's contribution to the population question, and it is one which suggests hope and action, and is in harmony with the growing ideal of racial eugenics. "For it is obvious that the progress of the species and of the individual alike is secured and accelerated whenever action is transferred from the negative side of merely seeking directly to repress genesis, to the positive yet indirect side of proportionally increasing individuation. This holds true of all species, yet most fully of man, since that modification of psychical activities in which his evolution essentially lies, is par excellence and increasingly the respect in which artificial or rational comes in to replace natural selection. Without therefore ignoring the latter, or hoping ever wholly to escape from the iron grasp of nature, we yet have within our power more and more to mitigate the pressure of population, and that without any sacrifice of progress, but actually by hastening it. Since then the remedy of pressure and the hope of progress alike lie in advancing individuation, the course for practical action is clear—it is in the organisation of these alternate reactions between bettered environment (material, mental, social, moral) and better organism in which the whole evolution of life is defined, in the conscious and rational adjustment of the struggle into the culture of existence."[21]
[21] Evolution of Sex. Chapter xx.
[CHAPTER XVII]
BEYOND SCIENCE
Metaphysics—Early Attitude to Religion—Increased Sympathy with Religion